This invention relates to a device for waxing a yarn by utilizing a travel of the yarn.
A yarn which is produced by a spinning machine and wound onto a bobbin is normally eventually assembled into a woven fabric or a knitted cloth by a weaving machine or a knitting machine. However, especially during a knitting operation, the yarn is subjected to a considerable frictional resistance when it comes in with knitting needles and/or guides which are in operation at a high speed. Such a resistance causes yarn breakage and napping, which results in a hindrance to the operation of the knitting machine and in knitting defects. Therefore, in order to eliminate the abovementioned disadvantages of the weaving machine and/or the knitting machine, the yarn has conventionally been waxed to improve smoothness before being wound onto the bobbin, and there have been provided various designs for devices for waxing yarn. Yarn waxing devices must be capable of waxing the yarn uniformly during the yarn winding-up in the spinning machine and must be inexpensive because the device has to be provided for each one of a number of spindles or spinning units of the spinning machine.
Since the waxing can be achieved by adhesion of paraffin molecules of the wax to the yarn, the wax is reduced in volume due to coming into contact with the yarn and as a result of a change in configuration. It is understood therefore, the condition under which the wax is in contact with the yarn changes with time. To accommodate such a change in contact condition, there have been provided various designs for a waxing device, one of which employs an annular wax roll or body supported for rotation to allow for it to be rotated by the yarn, which travels while contacting only the end face of the wax roll. For example, British Pat. No. 1,341,947 and Swiss Pat. No. 599,991 disclose the abovedescribed type of waxing devices.
One feature resulting from rotating the wax roll by with the yarn travel is that it is required that the wax roll be moved integrally with the yarn. Another feature resulting from waxing the yarn is that a strong relative movement is required between the yarn and the wax roll. However, with the aforesaid prior art devices, these conflicting requirements could not be satisfied because the rotation of the wax roll was caused only by the contact of the yarn with the wax roll. In such a wax driving system, the rotation of the wax roll was adversely affected by various factors, such as conditions of the end face of the wax roll with which the yarn comes in contact a uniform change in the distribution of weight of the wax roll with respect to the radial direction thereof, a sliding of the contact line, along which the yarn travels while contacting the wax roll, due to the transverse motion of the yarn, and a change in tension of the yarn. More particularly, the rotation of the wax roll was not smooth in spite of the use of a bearing means for the wax roll, and during normal spinning operation of the spinning machine there occurred an undesirable phenomenon wherein the wax roll repeatedly rotated in a intermittent fashion. This was due to several grooves or concave lines which were formed in the end face of the wax roll by the travelling yarn. As a result, the yarn was periodically caught in these grooves to temporarily prevent the rotation of the wax member and thereafter released therefrom when a portion of the yarn not caught by the grooves became oriented a certain angle with respect to the associated groove due to a transverse motion of the yarn and thereby, causing the wax roll to rotate again. As a result, the contact condition of the yarn with the wax roll became more uneven and the grooves became much more developed. The yarn was allowed to become subjected to less waxing and finally, could not be released from the grooves and thus, resulting in the cutting off of the wax roll.
Furthermore, in the described type of waxing device wherein the rotation of the wax roll relies only upon the contact thereof with the yarn, there occurred further problems during yarn travelling other than those occurring during the aforesaid normal spinning operation, such as during yarn piecing operations and doffing operations. For example, during the doffing operation, the yarn travelling, which is to be connected at its end to an empty bobbin, is under constant changing conditions in that tension is either greatly increased or loosened. Therefore, not only does the contact pressure of the yarn to the wax roll greatly vary, but also a definite position of the yarn in which the yarn properly contacts the wax roll can not be maintained. When the excessive tension is abruptly generated in the yarn, grooves or concaved lines will be formed in the end face of the wax roll. In contrast to the above, when the yarn is loosened so that it is shifted away from its normal path of travel, there is a possibility that the yarn will not return to the normal path of travel. If that occurs, the yarn is incapable of rotating the wax roll.
In addition, it can be understood that after the yarn piecing or doffing operation, the yarn is required to be smoothly transferred to its normal path of travel which allows for a proper contact of the yarn with the wax roll, otherwise the waxing device will not exhibit good waxing properties.